More than 200 million years ago, a massive extinction decimated 76 percent of marine and terrestrial species, marking the end of the Triassic period. Most scientists had agreed on a likely scenario: Over a relatively short period of time, massive volcanic eruptions spewed forth huge amounts of lava and gas, including carbon dioxide, sulfur and methane. Now researchers have determined that these eruptions occurred precisely when the extinction began. [Source: MIT News]